IWQoS 2023 is an in-person conference and the organizing committee expects all authors to attend and present their work in person. The travel restrictions have been lifted in different countries, and there is little reason why authors cannot travel. Authors should do everything possible to attend and present the work in person, including identifying some co-author that can travel and present.
Under extreme circumstances, a prior written request must be sent to TPC chairs, explaining the obstacles for travel, actions already taken to address those obstacles, and why eventually none of the co-authors can travel. Formal approval is needed then to find some non-authors (e.g., a colleague, lab mate) who’s familiar enough with the work to do a reasonable job presenting the paper in person.